Rail bond and method of making



Feb. 6, 1945. E. 'J. SABOL RAIL BOND AND METHOD OF. MAKING THE SAME Original Filed Nov. 8. 1955 l 11 mm [mania]? EE/\/E5T J. 54504,

Reissued Feb. 6, 1945 UNITED STATE RAIL BOND Ernest J. Sabol,

' American Steel Original No.

This invention is concerned with rail bonds having the conductor strands mechanically joined to the terminals, the primary object being to provide joints of high electrical conductivity and strength between the conductor strands and terminals in a manner permitting quantity production of the bonds.

Specific examples of the' invention are illustrated by the accompanying drawing in which:

Figure 1 is a side view of an electric power bond of the type wherein the conductor strand spans the outside oi the rail joint splice bar; v Figure 2 is an enlargement from Figure 1 showing the joint in section;

Figure 3 is a cross section taken from the line IIIIII of Figure 1;

Figure 4 is a longitudinal section showing a partially completed joint between the terminal and conductor strand as applied to a bond of the type wherein the conductor strand passes between the rail bond splice bar and the rail web; Figure 5 is the same as Figure 4excepting that the joint is completed;

Figures 6, '1 and 8 are sections taken from the lines VIV I, VII-VII and VIII. -VIII, respectively, in Figure 5; and

Figures and 10 show the preparation of the terminal and conductor strand end, respectively, to condition them for Joining.

More specifically the bond illustrated by Fig ures 1 through 3 comprises a terminal having a head I, a solid stud 2' and a tubular shank 3, the end of the conductor strand 4 being inserted in the tubular shank 3 and the latter being cold compressed so as to form a joint between the terminal and conductor strand.

The terminal is a solid integral forging of pure tubular .by drilling which normally leaves a smooth cylindrical inside. The conductor strand 4 is made of intertwisted cold drawn copper wires. It iollows from the above that when theend of the conductor strand is inserted in the inside of the tubular shank, the interengaging surfaces are smooth, the inside of 'the shank being smoothly drilled and the outer surfaces of the outer wires of the conductor strand being cold drawn to the usual smooth finish. Consequently, compression of the tubular shank 3 onto the end of the conductor strand 4 cannot produce a joint having a tensile strength equaling the tensile strength of the conductor strand. suits both from the ability of the outer wires of the strand to slide relative This lack of strength reelectrolytic copper, the shank-3 being rendered I to the manufacture cold compressed so as to chining operations Re. 22,599 I S PATENT OFFICE m rm'rnon or MAKING 'rnn SAME Norfolk, Va., assignor to T11 and Wire Company of New Jersey, a corporation of New Jersey 2,383,046, dated Serial No. 303,485, November'8, 1939. Application for reissue April 25, 1944, Serial No.

O tober 2c, 1943,

6 Claims. (Cl. 16-108) of the strand to slide relative the outer wires of the strand. Furthermore, the inside of the tubular shank and the outside ultimately made it does not possess as high electrical conductivity as is desirable.

The foregoing discussion is likewise applicable of bonds of the type shown by Figures 4 through 8. The terminal of this bond has a head 6, a stud I and a tubular shank 8 in which the end of the conductor strand 9 is inserted. Since this shorter shank 8. to permit its use in its intended manner, a hole is drilled through the originally solid shank and into the head 8, the latter initially being drilling of a hole oi'the diameter ofth conductor strand, as shown by'Figure 4. After the end of the strand is inserted, the head of the bond is flatten it and the conductor strand to the form shownby Figures 5 through 8, the tubular shank being flattened into a rectangular form along with the portion of the strand inside it, this resulting in a shape such as shown by Figure '7, while the head and conductor are greatly fanned out, as shown by Figures 6 and 8. v

The terminals of electric power bonds of the two types illustrated, in each instance, are forged from pure electrolytic copper. Although the shank, which is originally solid, can be drilled satisfactorily in the quantity production of the bonds, it is impossible to satisfactorily apply masmoothly drilled hole into which the conductor strand end is inserted. This is because pure electrolytic copper is a material which cannot satisfactorily be machined at high speeds. In addition, it is impossible in the quantity production of bonds to machine the outer surfaces of the outer wires of the conductor strand, this folnature of stranded lowing from the assemblies. 7

According to the present invention, the smooth inside ofthe tubular shank of the terminal and the smooth outer surfaces of the outer wires of the conductor strand are abraded to roughness by a suitable abrasive means. In the actual cominherent mercial production of bonds the abrasive means the inside of the shank, and from the tendency of the inner wires ll constitutes wire brushes. I

In the drawing, Figure 9 shows a rotary chuck turning a sleeve i2 clamped about a length of the end of the conductor strand become coated with oxide, grease bond must be made with a sufliciently large to accommodate the y to roughen the inside of the joint is assembled, there being ends of all the of wire rope having its ends flared as at I: to provide a still rotary brush. The sleeve I2 is positioned slightly oil center so as to cause the rotary brush to wobble. The tubular shank 3 of the terminal of the bond shownby Figures 1 and 2 is shown as being manually worked over this brush is while being turned so as to thoroughly abrade its inside to a slight degree of roughness. Quantity production of rail bonds has been practiced by this procedure.

Figure of the drawing shows the end of the conductor strand 4 being abraded to roughness by a rotary wire brush ll of the type used for cleaning purposes in machine shops. Here again, is held manually and turned during the abrading operation. Substantially the same procedure is followed in the manufacture of the bond of the type shown by Figure 4.

As shown by the drawing, the result of the above described abrading is to provide the interengaging surfaces of the inside of the shank of the terminal and the outsides of the outer wires of the conductor, with circumferential grooves abraded into these surfaces. This results from the turning of the surfaces circumferentially respecting the rotary wire brushes in the manner described. These abraded surfaces eliminate the necessity for using interposed material in the nature of hard granules or the like, this expedient being suggested in the case of prior art the shank-is indicated at 8 the part i attempts to efiect a high-strength joint but being objectionable in that the joint then does not have high electrical conductivity. This follows from the .fact that the conductivity of such granules cannot possibly approach that of the elec- I trolytic copper shank.

The above described brushing, in addition to slightly roughening the interengaging surfaces of the terminal shank and conductor strand, also thoroughly cleanse them of the oxide, grease, etc., with which these interengaging surfaces become contaminated when the parts are handled as they must be in the quantity production of rail bonds.

Immediately after the brushing operation, the

no time for the formation of further oxide or chance for the parts becoming dirty.

Anchorage of the inner wires of the conductor strand respecting the outer wires may be eifected by joining the ends of all of the wires of the conductor to a common mass of molten metal which, when solidified, causes theend of the conductor strand to be a unit in'so far as its various concerned. This may be done either gether. In any event, the idea is to join the wires by means of a common mass of metal. In Figure 2 this mass of metal is shown at 5.

These steps having been performed, the end of the conductor strand is inserted in the tubular shank and the latter cold compressed. Usuallythis is done in such a manner as to maintain the cylindrical shape of the shank and of the strand within. However, according to the present invention the shank is compressed from its mouth, from which the conductor diameter appreciably smaller than the uncompressed diameter oi. the conductor strand, the shank being then compressed to efl'ect gradually increasing sizes from this point in a direction to ward the end of the conductor strand. Preferably, this compression is efiected by two dies having suitable contours for effecting the varying degrees of compression when brought together.

In Figure 2, the mouth of the conductor is shown at 3 and the point of maximum compression is shown at 3, the increase in diameter beyond the point 3= providing a socket in which the end of the conductor strand works as a wedge. In Figures 5 through 8 the mouth of I and the point of smallest diameter at 8*, it being noted that in this instance the fanned portion of the stranii from the point 8 to the extreme end of the strand is the portion providing the wedge efiect. Since this extreme flattening of the strand 9 fixes all or most of the wires against movement, the ends of the wires need not necessarily be joined, no mass of metal being shown because of this.

In the case of either bond the mouth 3 or' I! does not compress the great degree, compression being gradually applied from the mouth to the point of smallest diameter. The contour of the inside of the shank, in each instance, is smoothly curving with no sharp bends, particularly between the point of smallest diameter and the mouth of the shank. Because of this construction, vibration between the terminal and strand cannot cause the concentration of vibratory stresses which results when the shank is compressed cylindrically, the stresses being gradually transmitted between the interengaging surfaces and terminal shank.

I claim:

1. A method of making a joint of high electrical'conductivity and strength between a tubular metal prior to insertion'of the conductor in the part.

2. A method of making a joint of high electrical conductivity and strength between a tubular part made of electrolytic copper and a conductor made of 'intertwisted copper wires, including working the inside of the part with a. wire brush to remove all contamination and roughen it, working the outer surfaces of the outer wires of the conductor to remove all contamination and roughen these surfaces, inserting the conductor in the part so the abraded surfaces of the conductor and of the part directly intercontact and are free from interposed material, and cold compressing the part onto the conductor, said method including interconnecting the endsof all of the wires of the conductorv with molten metal prior to insertion of the conductor in the part and compressing the part from its mouth from which the conductor strand to any 8. A joint of high electrical conductivity and strength. comprising a tubular part made of electrolytic copper cold compressed onto a conductor made of stranded copperwires, the interengaging surfaces of the inside of the part and of the outer I wires of the conductor being abraded to roughness and free from interposed material, the ends of all the wires of the conductor being interconnected by a solid metal mass preventing slipp ge of the inner wires and the part being compressed from its mouth from which the conductor ex- I tends from its uncompressed diameter'to gradbrush while turning the surface circumferen-' tially respecting the brush, inserting the con-,

ductor inside the tubular part so that the abraded surfaces of the conductor and of the part directly intercontact and cold compressing the part onto the conductor to complete the joint.

5. A method of making a joint of high electrlcal conductivity and strength between a tubular part made of electrolytic copper and a conductor made of stranded copper wires, the method comprising interjoining the ends of all the wires of said conductor by acommon mass of fused metal, abrading circumferential grooves into the surfaces of the inside of the part and the outsides of the outer wires of the conductor by contacting these surfaces with a rotary wire brushwhile turning the surface circumferentially respecting the brush, inserting the conductor inside the tubular :part so that the abraded surfaces of the conductor and of the part directly intercontact and cold compressing the part onto the conductor to complete the Joint.

6. A joint of high electrical conductivity and strength, comprising a tubular part made of electrolytic copper cold compressed onto a conductor made of stranded copperwires, the interengaging surface of the inside of the part and of the outer wires of the conductor being abraded to roughness and free from interposed material. and the part being compressed from its mouth from which the conductor extends from its uncompressed diameter to gradually progressing smaller diameters to a point spaced from its mouth where i1; i compressed to a diameter compressing the conductor to a diameter appreciably smaller than the uncompressed diameter of the conductor.

J SABOL. 

